Male hypogonadism

Management of male factor infertility: position statement from the Italian Society of Andrology and Sexual Medicine (SIAMS) : Endorsing Organization: Italian Society of Embryology, Reproduction, and Research (SIERR)

PURPOSE

Infertility affects 15-20% of couples and male factors are present in about half of the cases. For many aspects related to the diagnostic and therapeutic approach of male factor infertility, there is no general consensus, and the clinical approach is not uniform.

METHODS

In the present document by the Italian Society of Andrology and Sexual Medicine (SIAMS), endorsed by the Italian Society of Embryology, Reproduction, and Research (SIERR), we propose evidence-based recommendations for the diagnosis, treatment, and management of male factor infertility to improve patient and couple care.

RESULTS

Components of the initial evaluation should include at minimum medical history, physical examination, and semen analysis. Semen microbiological examination, endocrine assessment, and imaging are suggested in most men and recommended when specific risk factors for infertility exist or first-step analyses showed abnormalities. Full examination including genetic tests, testicular cytology/histology, or additional tests on sperm is clinically oriented and based on the results of previous investigations. For treatment purposes, the identification of the specific cause and the pathogenetic mechanism is advisable. At least, distinguishing pre-testicular, testicular, and post-testicular forms is essential. Treatment should be couple-oriented, including lifestyle modifications, etiologic therapies, empirical treatments, and ART on the basis of best evidence and with a gradual approach.

CONCLUSION

These Guidelines are based on two principal aspects: they are couple-oriented and place high value in assessing, preventing, and treating risk factors for infertility. These Guidelines also highlighted that male infertility and in particular testicular function might be a mirror of general health of a man.

Clinical utility of serum 17-hydroxyprogesterone as a marker for medical therapy for male infertility: recommendations based on clinical scenarios

Traditional serum hormone testing in the evaluation of male infertility consists of testosterone, follicle-stimulating hormone, luteinizing hormone, and estradiol. Based on these values, medical therapy is often initiated in an attempt to increase intratesticular testosterone levels and, in turn, promote spermatogenesis. While this hormone panel provides serum testosterone levels, it does not evaluate intratesticular testosterone, obviously an important factor that is critical for spermatogenesis. 17-hydroxyprogesterone (17-OHP) is an intermediate in the steroidal pathway of cholesterol to testosterone conversion that has recently demonstrated promise as an accurate serum biomarker for intratesticular testosterone. At present, 17-OHP has not been widely adopted as a clinical tool in the evaluation of male infertility, which likely stems, in part, from a lack of concrete indications for its use. In this review, we present five commonly encountered scenarios of male infertility where the utilization of 17-OHP has aided in the management and provided a more personalized approach to treatment.

Testosterone therapy and cardiovascular diseases

Since it was first synthesised in 1935, testosterone (T) has been viewed as the mythical Fountain of Youth, promising rejuvenation, restoring sexual appetites, growing stronger muscles, and quicker thinking. T is endowed with direct effects on myocardial and vascular structure and function, as well as on risk factors for cardiovascular (CV) disease. Indeed, low serum T levels are a risk factor for diabetes, metabolic syndrome, inflammation, and dyslipidaemia. Moreover, many studies have shown that T deficiency per se is an independent risk factor of CV and all-cause mortality. On this background and due to direct-to-patient marketing by drug companies, we have witnessed to the widespread use of T replacement therapy (TT) without clear indications particularly in late-life onset hypogonadism. The current review will dwell upon current evidence and controversies surrounding the role of T in the pathophysiology of CV diseases, the link between circulating T levels and CV risk, and the use of replacing T as a possible adjuvant treatment in specific CV disorders. Specifically, recent findings suggest that heart failure and type 2 diabetes mellitus represent two potential targets of T therapy once that a state of hypogonadism is diagnosed. However, only if ongoing studies solve the CV safety issue the T orchid may eventually 'bloom'.

The Link Between Sex Hormones and Susceptibility to Cardiac Arrhythmias: From Molecular Basis to Clinical Implications

It is well-known that gender is an independent risk factor for some types of cardiac arrhythmias. For example, males have a greater prevalence of atrial fibrillation and the Brugada Syndrome. In contrast, females are at increased risk for the Long QT Syndrome. However, the underlying mechanisms of these gender differences have not been fully identified. Recently, there has been accumulating evidence indicating that sex hormones may have a significant impact on the cardiac rhythm. In this review, we describe in-depth the molecular interactions between sex hormones and the cardiac ion channels, as well as the clinical implications of these interactions on the cardiac conduction system, in order to understand the link between these hormones and the susceptibility to arrhythmias.

Late Effects of Parasellar Lesion Treatment: Hypogonadism and Infertility

Central hypogonadism, also defined as hypogonadotropic hypogonadism, is a recognized complication of hypothalamic-pituitary-gonadal axis damage following treatment of sellar and parasellar masses. In addition to radiotherapy and surgery, CTLA4-blocking antibodies and alkylating agents such as temozolomide can also lead to hypogonadism, through different mechanisms. Central hypogonadism in boys and girls may lead to pubertal delay or arrest, impairing full development of the genitalia and secondary sexual characteristics. Alternatively, cranial irradiation or ectopic hormone production may instead cause early puberty, affecting hypothalamic control of the gonadostat. Given the reproductive risks, discussion of fertility preservation options and referral to reproductive specialists before treatment is essential. Steroid hormone replacement can interfere with other replacement therapies and may require specific dose adjustments. Adequate gonadotropin stimulation therapy may enable patients to restore gametogenesis and conceive spontaneously. When assisted reproductive technology is needed, protocols must be tailored to account for possible long-term gonadotropin insufficiency prior to stimulation. The aim of this review was to provide an overview of the risk factors for hypogonadism and infertility in patients treated for parasellar lesions and to give a summary of the current recommendations for management and follow-up of these dysfunctions in such patients. We have also briefly summarized evidence on the physiological role of pituitary hormones during pregnancy, focusing on the management of pituitary deficiencies.

Changes in left ventricular repolarization after short-term testosterone replacement therapy in hypogonadal males

BACKGROUND AND AIM

Evidences suggest that androgen deficiency is associated with sudden cardiac death (SCD). Our purpose was to analyse some electrocardiographic (ECG) markers of repolarization phase in hypogonadal patients either at baseline or after testosterone replacement therapy (TRT).

PATIENTS AND METHODS

Baseline and after 6 months of testosterone replacement therapy, 14 hypogonadal patients and 10 age-matched controls underwent a short-term ECG recordings at rest and immediately after a maximal exercise test. The following ECG parameters have been collected: QTe (the interval between the q wave the end of T wave), QTp (the interval between the q wave and the peak of T wave), and Te (the interval between the peak and the end of T wave).

RESULTS

At baseline, in the hypogonadal patients, corrected QTe and QTp values were longer at rest than in the controls at rest (p < 0.05), whereas, during the recovery phase, only the QTp remained significantly longer (p < 0.05). After TRT, hypogonadal patients showed an improvement only in Te (p < 0.05). Conversely, any difference between hypogonadal patients and control subjects was found with respect to the markers of temporal dispersion of repolarization phases, except for a worse QTp → Te coherence (p = 0.001) obtained during the recovery phase.

CONCLUSIONS

In conclusion, at rest, hypogonadal patients suffer from a stable increase in the myocardial repolarization phase without an increase in its temporal dispersion and, hence, the SCD risk seems to be low.

The CATCH checklist to investigate adult-onset hypogonadism

Adult-onset hypogonadism is a syndrome often underdiagnosed, undertreated, or incompletely explored. There are various reasons for this: firstly, undefined age range of men in whom testosterone levels should be investigated and then no definitive serum cutoff point for the diagnosis of hypogonadism; and finally, variable and non-specific signs and symptoms; men and physicians do not pay adequate attention to sexual health. All these factors make the diagnostic criteria for hypogonadism controversial. The evaluation of the clinical features and causes of this syndrome, its link with age, the role of testosterone and other hormone levels, and the presence of any comorbidities are all useful factors in the investigation of this population. The purpose of this manuscript, after an accurate analysis of current literature, is to facilitate the diagnosis of hypogonadism in men through the use of the CATCH acronym and a checklist to offer a practical diagnostic tool for daily clinical practice. A narrative review of the relevant literature regarding the diagnosis of late-onset hypogonadism or adult-onset hypogonadism was performed. PubMed database was used to retrieve articles published on this topic. A useful new acronym CATCH (Clinical features [symptoms] and Causes, Age, Testosterone level, Comorbidities, and Hormones) and a practical checklist to facilitate the evaluation of hypogonadism in aging men were used. The evaluation of the clinical features and causes of hypogonadism, the link with age, the role of Testosterone and other hormones, and the evaluation of comorbidities are important in investigating adult-onset hypogonadism. The CATCH checklist could be helpful for clinicians for an early diagnosis of both hypogonadism and associated comorbidities. We suggest the use of this acronym to advocate the investigation of declining testosterone in aging men.

Dynamic GnRH and hCG testing: establishment of new diagnostic reference levels

OBJECTIVE

Gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) stimulation tests may be used to evaluate the pituitary and testicular capacity. Our aim was to evaluate changes in follicular-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone after GnRH and hCG stimulation in healthy men and assess the impact of six single nucleotide polymorphisms on the responses.

DESIGN

GnRH and hCG stimulation tests were performed on 77 healthy men, 18-40 years (reference group) at a specialized andrology referral center at a university hospital. The potential influence of the tests was illustrated by results from 45 patients suspected of disordered hypothalamic-pituitary-gonadal axis.

METHODS

Baseline, stimulated, relative and absolute changes in serum FSH and LH were determined by ultrasensitive TRIFMA, and testosterone was determined by LC-MS/MS.

RESULTS

For the reference group, LH and FSH increased almost 400% and 40% during GnRH testing, stimulated levels varied from 4.4 to 58.8 U/L and 0.2 to 11.8 U/L and FSH decreased in nine men. Testosterone increased approximately 110% (range: 18.7-67.6 nmol/L) during hCG testing. None of the polymorphisms had any major impact on the test results. Results from GnRH and hCG tests in patients compared with the reference group showed that the stimulated level and absolute increase in LH showed superior identification of patients compared with the relative increase, and the absolute change in testosterone was superior in identifying men with Leydig cell insufficiency, compared with the relative increase.

CONCLUSIONS

We provide novel reference ranges for GnRH and hCG test in healthy men, which allows future diagnostic evaluation of hypothalamic-pituitary-gonadal disorders in men.

Argirein alleviates stress-induced and diabetic hypogonadism in rats via normalizing testis endothelin receptor A and connexin 43

AIM

Argirein (rhein-arginine) is a derivative of rhein isolated from Chinese rhubarb (Rheum Officinale Baill.) that exhibits antioxidant and anti-inflammatory activities. In the present study we investigated the effects of argirein on stress-induced (hypergonadotrophic) and diabetic (hypogonadotrophic) hypogonadism in male rats.

METHODS

Stress-induced and diabetic hypogonadism was induced in male rats via injection of isoproterenol (ISO) or streptozotocin (STZ). ISO-injected rats were treated with argirein (30 mg·kg(-1)·d(-1), po) or testosterone replacement (0.5 mg·kg(-1)·d(-1), sc) for 5 days, and STZ-injected rats were treated with argirein (40-120 mg·kg(-1)·d(-1), po) or aminoguanidine (100 mg·kg(-1)·d(-1), po) for 4 weeks. After the rats were euthanized, blood samples and testes were collected. Serum hormone levels were measured, and the expression of endothelin receptor A (ETA), connexin 43 (Cx43) and other proteins in testes was detected. For in vitro experiments, testis homogenate was prepared from normal male rats, and incubated with ISO (1 μmol/L) or high glucose (27 mmol/L).

RESULTS

ISO injection induced hyper-gonadotrophic hypogonadism characterized by low testosterone and high FSH and LH levels in the serum, whereas STZ injection induced hypogonadotrophic hypogonadism as evidenced by low testosterone and low FSH and LH levels in the serum. In the testes of ISO- and STZ-injected rats, the expression of ETA, MMP-9, NADPH oxidase and pPKCε was significantly increased, and the expression of Cx43 was decreased. Administration of argirein attenuated both the abnormal serum hormone levels and the testis changes in ISO- and STZ-injected rats, and aminoguanidine produced similar actions in STZ-injected rats; testosterone replacement reversed the abnormal serum hormone levels, but did not affect the testis changes in ISO-injected rats. Argirein (0.3-3 μmol/L) exerted similar effects in testis homogenate incubated with ISO or high glucose in vitro.

CONCLUSION

Two types of hypogonadism of male rats exhibit increased expression of ETA and depressed expression of Cx43 in testes, despite different patterns of serum FSH and LH. Argirein alleviates the two types of male hypogonadism via normalizing ETA and Cx43 in testes.

[Sexuality in overweight and obesity]

The association between obesity and sexual dysfunction has been described in many studies. Neurobiological, hormonal, vascular and mental disturbances are the main reasons in male and in female gender. Sexual interest and desire, sexual arousal, orgasm, painful intercourse and premature ejaculation can be involved. Data for prevalence of sexual function disturbances in obese people are scarce and most studies were small. For screening of sexual function we recommend the International Index of Erectile Function (IIEF)-Score, which contains 15 Items for males and the Female Sexual Function Index (FSFI), which contains 19 items for females. Treatment of sexual function disturbances include lifestyle changes with an increase of physical activity, weight control, healthy eating and smoking cessation. Testosterone substitution in cases of real hypogonadism and treatment with PDE-5 inhibitors are well documented treatment options in male individuals. New treatment options for female patients with variable effectiveness are fibanserin, testosterone, bupropione and oxytocin.

Erythrocytosis and Polycythemia Secondary to Testosterone Replacement Therapy in the Aging Male

INTRODUCTION

Testosterone replacement therapy (TRT) is a common treatment for hypogonadism in aging males. Men with low to low-normal levels of testosterone have documented benefit from hormone replacement. Recent meta-analyses have revealed that increases in hemoglobin (Hb) and hematocrit (Hct) are the variants most commonly encountered. Clinically, this response is described as erythrocytosis or polycythemia secondary to TRT. However, the recent Food and Drug Administration warning regarding the risk for venothromboembolism (VTE) has made the increases in Hb and Hct of more pertinent concern. The risks associated with androgen replacement need further examination.

AIM

To review the available literature on erythrocytosis and polycythemia secondary to TRT. To discuss potential etiologies for this response, the role it plays in risk for VTE, and recommendations for considering treatment in at-risk populations.

METHODS

A literature review was performed through PubMed regarding TRT and erythrocytosis and polycythemia.

MAIN OUTCOME MEASURES

To assess the mechanisms of TRT-induced erythrocytosis and polycythemia with regard to basic science, pharmacologic preparation, and route of delivery. To review Hct and risk for thrombotic events. To offer clinical suggestions for therapy in patients at risk for veno-thrombotic events.

RESULTS

Men undergoing TRT have a 315% greater risk for developing erythrocytosis (defined as Hct > 0.52) when compared with control. Mechanisms involving iron bioavailability, erythropoietin production, and bone marrow stimulation have been postulated to explain the erythrogenic effect of TRT. The association between TRT-induced erythrocytosis and subsequent risk for VTE remains inconclusive.

CONCLUSIONS

All TRT formulations cause increases in Hb and Hct, but injectables tend to produce the greatest effect. The evidence regarding the risk for VTE with increased Hct is inconclusive. For patients with risk factors for veno-thrombotic events, formulations that provide the smallest effect on blood parameters hypothetically provide the safest option. Further trials are needed to fully evaluate the hematological side effects associated with TRT. Jones SD Jr, Dukovac T, Sangkum P, Yafi FA, and Hellstrom WJG. Erythrocytosis and polycythemia secondary to testosterone replacement therapy in the aging male. Sex Med Rev 2015;3:101-112.

Ursodeoxycholic acid alleviates cholestasis-induced histophysiological alterations in the male reproductive system of bile duct-ligated rats

Ursodeoxycholic acid is the most widely used drug for treating cholestatic liver diseases. However, its effect on the male reproductive system alterations associated with cholestasis has never been studied. Thus, this study aimed to investigate the effect of ursodeoxycholic acid on cholestasis-induced alterations in the male reproductive system. Cholestasis was induced by bile duct ligation. Bile duct-ligated rats had higher cholestasis biomarkers and lower levels of testosterone, LH and FSH than did the Sham rats. They also had lower reproductive organs weights, and lower sperm motility, density and normal morphology than those of Sham rats. Histologically, these animals suffered from testicular tubular atrophy, interstitial edema, thickening of basement membranes, vacuolation, and depletion of germ cells. After ursodeoxycholic acid administration, cholestasis-induced structural and functional alterations were significantly ameliorated. In conclusion, ursodeoxycholic acid can ameliorate the reproductive complications of chronic cholestasis in male patients, which represents an additional benefit to this drug.

Management of Klinefelter syndrome during transition

Klinefelter syndrome (KS) is the most common sex chromosomal disorder in males. Key findings in older adolescents and young men are small testes with variable hypo-androgenism, but almost universal azoospermia, most frequently in combination with a history of learning difficulties and behavior problems. Males with KS may come to medical attention through different medical presentations, given its association with several congenital malformations, and psychiatric, endocrine, and metabolic disorders. Preventive care is to be provided from diagnosis, preferentially through a multidisciplinary approach, including that from an endocrinologist, clinical psychologist or psychiatrist, neurologist, urologist, geneticist, sexologist, and a fertility team. Accurate information about the condition and assessment of associated medical conditions should be offered at diagnosis and should be followed by psychological counseling. Medical treatment during transition into adulthood is focused on fertility preservation and testosterone replacement therapy in the case of hypo-androgenism, and alleviation of current or future consequences of testicular fibrosis. However, more research is needed to determine the need for pro-active testosterone treatment in adolescence, as well as the conditions for an optimal testosterone replacement and sperm retrieval in adolescents and young men with KS. Furthermore, screening for associated diseases such as metabolic syndrome, autoimmune diseases, thyroid dysfunction, and malignancies is warranted during this period of life. The practical medical management during transition and, more specifically, the role of the endocrinologist are discussed in this article.

The SIAMS-ED Trial: A National, Independent, Multicentre Study on Cardiometabolic and Hormonal Impairment of Men with Erectile Dysfunction Treated with Vardenafil

Increased cardiovascular risk has been associated with reduced response to proerectile drugs. The Italian Society of Andrology and Sexual Medicine (SIAMS) promoted an independent, multicenter study performed in 604 men (55 ± 12 yrs) suffering from erectile dysfunction (ED) to assess multiple health outcomes and response to 6-month vardenafil challenge in a real-life setting. Overall, 30.8% men had metabolic syndrome. Cardiovascular risk stratification revealed a greater number of ED subjects with moderate risk of a major adverse cardiovascular event than the general population (P < 0.01). Age-adjusted pulse pressure was positively correlated with ED severity and negatively with androgens and waist circumference (P < 0.01). A decline in total testosterone was observed with increasing arterial pulse pressure (P < 0.05), which was not accompanied by compensatory LH rise. Follow-up on 185 men treated with vardenafil in an nonrandomized, open, single-arm trial documented a significant rise in IIEF-5 (delta = 6.1 ± 4.8) that was maintained in men with high cardiovascular risk. Mild adverse events occurred in <5%, with no differences between cardiovascular risk classes. In summary, ED is a frequent symptom in patients with an elevated, but often unknown, risk of future cardiovascular events. Androgens predict vascular resistance in ED patients. Vardenafil's response and safety profile were preserved in subjects with higher cardiovascular risk.

Toxicological assessment of drugs that affect the endocrine system in puberty-related disorders

INTRODUCTION

Toxicologists must ensure that clinical risk-to-benefit analysis should be made both for genders and age groups, with any treatment. Puberty concerns physiological changes leading to organism's maturation. Pubertal growth disorders are increasing in last decades: besides causing physical and psychological distress, they may signal underlying endocrine-metabolic abnormalities with serious health consequences later on. Therapeutic approaches for some health conditions in childhood and adolescence are considered.

AREAS COVERED

The authors discuss how some diseases and treatments can impact pubertal growth. The authors look at particular immunological disorders such as asthma and how both the disease and treatment affects pubertal growth. They also discuss how the provision of available data can help to assess the dose-response of the drug, in these cases, and minimize the chance of side effects. The authors also discuss pediatric inflammatory bowel disease and how both the disease and treatment can mitigate the growth delay. Last, but not least, the authors discuss how the effects of the drugs used in the treatment of psychiatric disorders may accentuate endocrine issues in juvenile patients. Hyperprolactinemia induction by some antipsychotics is highlighted as an example.

EXPERT OPINION

Appropriate risk-benefit analysis of drugs prescribed during childhood and adolescence and intended to be used in the long term is required. Furthermore, future treatment strategies and safer compounds development should be supported by the knowledge of mechanisms underlying adverse side effects in pubertal growth and development.

Subclinical male hypogonadism

Male hypogonadism is traditionally defined as the inadequate production of testosterone and impaired spermatozoa generation in the presence of elevated or reduced levels of gonadotropins. A more frequent measurement of testosterone levels and the development of highly sensitive and specific assays have led to the detection of less clinically evident gonadal dysfunction, in which small biochemical alterations may or may not be accompanied by signs and symptoms. This condition is called "compensated" or "subclinical" hypogonadism. To determine whether subclinical hypogonadism is a paraphysiological state, a clinical condition in itself, or a precursor to overt hypogonadism, we carried out a literature review with the aim of establishing a practical approach to subclinical hypogonadism.

Polycythemia as rare secondary direct manifestation of acromegaly: management and single-centre epidemiological data

Polycythemia associated with acromegaly is usually caused by the systemic manifestations of the disease, such as sleep-apnea or concomitant erythropoietin-secreting kidney tumors. The recognition of underlying pathologies requires a thorough diagnostic process. We report a unique case of acromegaly with polycythemia, not caused by commonly described manifestations of the disease, and receding with octreotide therapy. The medical history of 141 acromegalic patients followed by the Endocrinology Unit of the San Martino University Hospital in Genoa has been also reviewed, together with the literature evidence for similar cases. The diagnostic workflow and 2-years follow-up of a 43-years old acromegalic, polycythemic man with a history of past smoking, moderate hypertension, and mental retardation are described. The hematological parameters of our cohort was retrospectively compared with those of a healthy, age/gender-related control group as well. Therapy with octreotide LAR, 20 mg i.m. q28d was begun soon after diagnosis of acromegaly in the polycythemic patient. Haematocrit level, hormonal setting, as well as pituitary tumor size and visual perimetry during treatment were recorded. Octreotide LAR treatment normalized hormonal alterations, as well as hematological parameters. Polycythemia has not recurred after 2 years of therapy. The median hemoglobin and hematocrit levels of the retrospectively analyzed cohort of acromegalic were significantly lower than normal ranges of a healthy, age/sex- related control population. In conclusions, polycythemia can be a direct, albeit rare, secondary manifestation of acromegaly, that must be considered during the diagnostic work-up of acromegalic patients presenting with such disorder.

The impact of sirolimus on sex hormones in male adolescent kidney recipients

While it is known that sirolimus affects sex hormones in adult kidney transplant patients, there is a scarcity of data on its effects on sex hormone levels in adolescent kidney recipients. The objective of this study is to describe the impact of sirolimus on the sex hormones in this patient population. This is a retrospective review of male adolescent renal transplant patients transitioned to sirolimus. Baseline and subsequent annual testosterone levels were collected. Linear regression was undertaken to determine the predictors of testosterone levels. Four African Americans and 11 Caucasians, median age of 15 yr (11-18) in 2008, were included. Mean time post-transplant was 81 ± 37 months. Mean testosterone values were the following: 336 ± 135 ng/dL (n = 8) at baseline, 349 ± 130 ng/dL (n = 15) one yr later, and 360 ± 132 ng/dL (n = 13) two yr later (normal range for adult males: 350-970 ng/dL). Seven (47%) patients experienced a decrease in testosterone levels. Time on sirolimus was associated with decreased testosterone (r = 0.643, p = 0.010). Testosterone levels in pubertal male kidney transplant recipients on sirolimus may be suppressed, especially if they have been treated with sirolimus for several years. These data need to be confirmed in a larger study.

Clomiphene citrate and enclomiphene for the treatment of hypogonadal androgen deficiency

Hypogonadism has a number of important clinical consequences related to androgen deficiency and impaired spermatogenesis. The cause of this condition is multifactorial and can result from hypothalamic, pituitary or gonadal dysfunction as well as factors that affect hormonal signaling along the hypothalamic-pituitary-gonadal axis. While testosterone replacement is the most common treatment, it can paradoxically lead to infertility, and may be a less physiologic therapy for patients with secondary hypogonadism due to pituitary dysfunction. Clomiphene citrate, and its derivatives, may allow for restoration of gonadal function by restoring physiologic pituitary function in a subset of patients with hypogonadism.

Epidemiology, diagnosis, and treatment of male hypogonadotropic hypogonadism

Hypogonadotropic hypogonadism (HH), or secondary hypogonadism, is a clinical condition due to an impairment of the pituitary function, characterized by low testosterone plasma levels associated with normal or low FSH and LH plasma levels. An impairment of gonadotropin secretion and, therefore, a reduced efficiency of spermatogenesis was reported to be frequently associated to conditions different from the classical causes of secondary hypogonadism. These conditions (metabolic, endocrine and eating disorders, physical exercise etc.) have been associated with a non-classical form of HH that could be called "functional" HH (FHH). FHH differs from the classical one by the evidence that gonadotropin levels are in the low-normal range, but are inadequate for the testosterone levels, that often are also in the low-normal range. This commentary aims at reviewing knowledge on the forms of male HH in order to indicate and discuss clinical context, diagnostic and therapeutic approach in the less known non-classical form, i.e. FHH.